New research

Satellites reveal rapid acceleration of Antarctic glacier ice loss

  • 21 May 2015, 19:00
  • Robert McSweeney

Thinning of glaciers in one of the most vulnerable parts of Antarctica has accelerated at a "remarkable rate" since 2009, a new study finds.

Stable through the 2000s, the glaciers began losing large quantities of ice within just a year or two, the lead author tells Carbon Brief.

The study shows the surprising speed with which Antarctica's glaciers can react to rising ocean temperatures, and without warning, he says.

Remarkable acceleration

Glaciers are huge rivers of ice that ooze their way over land, powered by gravity and their own sheer weight. They accumulate ice from snowfall and lose it through melting.

In the new study, published today in  Science, researchers analysed changes to glaciers on the Southern Antarctic Peninsula in the last decade and a half.

For most of the 2000s, satellite data shows the glaciers lost about as much ice as they gained, meaning they stayed roughly stable. But around 2009 there was "a remarkable rate of acceleration" in ice loss, the study says.

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Limiting global warming to 1.5C is still possible, say scientists

  • 21 May 2015, 14:30
  • Simon Evans

It's still technically possible to limit global warming to below 1.5C this century, according to new research published in Nature Climate Change.

Only a small window of opportunity remains open, the study says - and it is closing rapidly. Global carbon pricing or its equivalent should have been implemented already and must certainly be in place by 2020. The world would then need to become carbon neutral by mid-century.

The new study pitches into a live and vociferous debate over whether the world should be aiming to limit warming to 1.5C or 2C, and whether either target remains achievable. Carbon Brief puts the new study's findings in context.

Limiting warming to 1.5C

So far, the globally agreed target for avoiding dangerous climate change is to limit warming to  no more than 2C above pre-industrial levels. But more than half of the world's nations represented under the UN's Framework Convention on Climate Change (UNFCCC) are in favour of a tougher 1.5C target. These include the least developed and most vulnerable countries, such as the small island states that are already losing farmland to rising sea levels.

UNFCCC review process is underway to try to decide if a 1.5C goal would be more appropriate. Its initial findings include that the impacts of even 1.5C of warming would be "significant" and that a 1.5C limit would be "preferable" to 2C. However, it warns that the science on the impacts of 1.5C compared to 2C is "less robust" and that until new results become available, any decision on strengthening the current 2C goal may need to wait.

Today's new research aims directly into this relative scientific void. It says: "So far, only a few studies have reported scenarios consistent with a 1.5C limit… Here we fill this gap".

To find out if 1.5C remains possible it uses two " integrated assessment models" that represent the world's energy system and economy under different assumptions about the future of global policy, development and growth.

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Mountain shape a key factor in species surviving climate change

  • 20 May 2015, 08:30
  • Robert McSweeney

One way animals and plants can cope with climate change is to relocate. Research shows some species are already shifting to higher ground or towards the poles in search of cooler climes.

But for creatures already living in mountains, the solution is not so simple. A new study of 182 high-altitude regions across the world shows how mountain shape is critical in determining whether a species will find refuge from rising temperatures further uphill.

This means the odds of survival are better for some species than others, say the authors.

Habitat range

The typical image of a mountain is a pyramid shape - a broad base that tapers to a peak. In theory, as species move upwards the habitat available to them shrinks, the paper explains.

But the study, published in Nature Climate Change, finds that over two-thirds of mountains don't follow this rule. In fact, mountains fall into one of four shapes: diamond, pyramid, inverse pyramid and hourglass, as the diagram below shows.   

Elsen & Tingley (2015) Fig1

 

Examples of four common mountain types. Colours indicate elevation, from low (blue and green) to mountaintops (yellow and orange) Source: Elsen & Tingley (2015)

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